Cocking device for the breech mechanism of automatic firearms



Jan. 3, 1961 E. HEPPERLE 2,966,830

COCKING DEVICE FOR THE BREECH MECHANISM OF' AUTOMATIC F'IREARMS Filed nec. 18, 1958 2 sheets-sheet 1 Fig.l

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Efwin HEPPER LE lnvEN-roa United States Patent O COCKING DEVICE FOR THE BREECH MECHA- NISM OF AUTOMATIC FIREARMS Erwin Hepperle, Dietlikon, Zurich, Switzerland, assignor to Machine Tool Works Oerlikon, Administration Company, Zurich-Oerlikon, Switzerland, a company of Switzerland Filed Dec. 18, 1958, Ser. No. 781,284

Claims priority, application Switzerland Jan. 9, 1958 1 Claim. (Cl. 89-155) The present invention relates to a cocking device for the breech mechanism of automatic firearms, having an auxiliary piston which is driven by the pressure gases generated by special driving charges and which, when displaced, cocks the breech mechanism, and having a rotatable casing for the said driving charges which are turned consecutively into the firing position, in which its loading chambers are in communication with the pressure chamber of the auxiliary piston.

Such cocking devices are known in themselves. In the device, which has become known, the driving charge casing has to be moved on by a reciprocating member, which has in turn to be driven by a separate motor, which involves an undesirable complication.

It is the primary object of the present invention to provide a cocking device for the breech mechanism of automatic firearms which is free from this complication.

With this and objects in view which will become apparent later from this specification and its accompanying drawings, I provide a cocking device for the breech mechanism of an automatic firearm comprising in combination: a stationary cylinder having a pressure charnber, a rotatable driving charge casing having cartridge chambers arranged on a pitch circle and consecutively brought into communication with the said pressure chamber when in their firing position, an auxiliary piston movable in the said cylinder and operatively coupled both to the said breech mechanism in the sense of cocking the same when performing its working stroke in the said cylinder under the gas pressure generated in said pressure chamber by the firing of a driving charge cartridge and to the said rotatable driving charge casing in the sense of turning the same one pitch of said circle on its return stroke, and an energy accumulator operatively connected to said auxiliary piston deriving energy from the latter on its working stroke and restoring said energy to it on its return stroke.

These and other features of the present invention will be clearly understood from the following descripti-on of an embodiment thereof given by way of example with reference to the accompanying drawings, in which Fig. 1 is on a smaller scale than the other figures.

Fig. 1 is a diagrammatic section of an automatic firearm with a cocking device;

Fig. 2 is a section of the cocking device on the line II--II of Fig. 4;

Fig. 3 is a section of the cocking device on the line III--III of Fig. 4;

Fig. 4 is a section on the lineIV--IV of Fig. 2 at lthe beginning of the cocking stroke of the auxiliary piston;

Fig. 5 is a section on the line V-V of Fig. 2 at the end of the cocking stroke of the auxiliary piston.

The automatic firearm diagrammatically illustrated in Fig. 1 is constructed according to the principle of a revolver. In the casing 1 the revolver drum 2 s rotatably mounted on an axle parallel to the barrel 3. The revolver drum containing several cartridge chambers, which 2,966,830 Patented Jan. 3, 1961 ICC upon its rotation come consecutively in alignment with the barrel 3, is driven by a slider member 4 movable in the longitudinal direction of the weapon in that curved guide tracks thereof engage with pins 5 fixedly connected to the drum. The slider member is in turn operated after each shot for example by two pistons 6, which are housed at both sides of the auxiliary piston cylinder 15 in cylinders 7 (Fig. 3) and are driven by the gas passed into the cylinders by the gas tapping bore 8 branching off the barrel 3. After a working stroke the slider member returns to its starting position by the bias of a closing spring 9 and under the action of the rotating drum 2.

The cartridge feeder star 10 is arranged co-axally to the revolver drum 2 and is connected therewith by a clutch.4 From this feeder star the cartridges 11 are introduced by the cams 12 and 13 of the slider member 4 into the cartridge chamber of the drum 2 in two steps. In order to introduce a belt containing the cartridges into the weapon and to make the latter ready for firing in that the first cartridge is brought into alignment with the barrel, the slider member 4 has to be pushed repeatedly rearward, and thereby the drum with the cartridge feeder star 10 to be turned stepwise. This is effected by the cocking device P attached at the forward end of the weapon, which is also operated for example in order to move a dud into an ejection position, and at the same time to bring the next cartridge into alignment with the barrel.

With the cocking device illustrated in Figs. 2 and 3 the cylinder casing 15 containing an auxiliary piston 14 is fxedly connected to the casing 1 of the weapon. The auxiliary piston is made in two parts: the forward part 14a, which is impinged upon by and seals against the gas, is in contact with the rear part, 14b, which by the return spring 16 acting on its collar 14d and abutting the casing 15 is forced towards the starting position in which its rear end face contacts the end face of the slider member 4, which is in its rest position.

On the cylinder casing 15 and co-axally to the auxiliary piston 14 a casing 17, designed as a thick-walled sleeve, is rotatably mounted, the wall of which has bores 18 arranged at a regular pitch for receiving the driving charge cartridges. These cartridges 20, which are arranged on a circle about the axis of rotation of the casing 17, contain the driving charges generating the auxiliary pressure, and a device for electrically igniting the same. By turning the casing 17 the cartridges are passed in succession into a position behind the bore 21a of the cylinder cover 21 said bore serving as part of' the gas supply duct to the pressure chamber of the auxiliary piston; co-axially to this bore the contact pin 22 of the igniting device is arranged. The cover 21, fitted to the cylinder casing 15 by means of a bayonet joint is restrained from rotating and secured in the correct position by the spring-loaded lever 23 engaging into a groove 15d of the cylinder casing. The angular bore 21a in the cover issues into the bore 15a in the cylinder casing, which leads to the pressure chamber 24 ahead of the auxiliary piston 14. After lifting-off the cover 21,the driving charge casing 17 with the empty cartridge cases can be removed, and reloaded with cartridges.

The bores 18 in the driving charge casing designed for taking in the cartridges issue forwardly into an enlarged bore 18a thereof, into each of which a sealing bushing 19 is inserted, which abut the rear end face of the cylinder cover 21. That part of the sealing bushing, which faces towards the driving charge, has a thin wall which under the action of the high pressure gases of the burning driving charge, makes a sealing contact with the wall of the bore 18a. The bore of the sealing bushing contracts forwardly. The pressure forces of the gases acting on the annular surface formed by the contraction force the end face of the sealing bushing against the rear end face of the cylinder cover 21, whereby the separating point between the latter and the driving charge casing is bridged in a gas-tight manner.

The enlarged rear end of the driving charge casing is internally splined, the number of splines being equal to the number of bores 18 forming the loading chambers.

Until shortly before the rear dead centre of the auxiliary piston 14 is reached, the projection 14C thereof plunges into the central bore 15b of the cylinder with a sealing effect. Then the passage from the pressure chamber 24 through this bore is cleared for a short period, so that the gas contained in the pressure chamber can escape into the open, and the auxiliary piston, running forward into the starting position is relieved of the gas pressure. At the same time also the pressure on the sealing bushing 19 is abolished.

A control sleeve 25 is rotatably mounted on the cylinder casing 15. Its forward end reaches into the internally splined rear end of the driving charge casing 17. As illustrated in Figs. 4 and 5, two double-armed pawls, namely the pawl 26 and the locking pawl 27, which are designed for engaging into the splining of the driving charge casing and lie in a plane perpendicular to the axis of the auxiliary piston, are pivotally mounted on pins 28 and 29. These pins are tixed in lugs 30 and 31 of the control sleeve 25. The pawls 26 and 27 are subject to the bias of springs 32 and 33. In the same plane with these pawls there is further a locking pawl 34 mounted rotatably on a pin 35 fixed in the cylinder casing 15. In the cylinder casing moreover a bushing 36 is fitted, into which a spring-biased locking tooth 37 is inserted movably. A pin 38 xedly mounted in the auxiliary piston 14 is guided in the cylinder casing by two slots 15C, which run parallel to the axis thereof. The ends of the pin moreover engage into curved control slots 25a machined into the control sleeve 25.

From this construction results the following manner of operation of the cocking device:

For the purpose of initiating a cocking movement of the auxiliary piston 14, the driving charge cartridge 2t), which is in the firing position, is ignited. The driving gases pass through the bores 21a and 15a into the pressure chamber 24 ahead of the auxiliary piston and force the same back. The auxiliary piston thereby imparts a certain velocity to the slider member 4, so that the same continues its movement by itself after the reversal of movement of the auxiliary piston, and thereby turns the revolver drum 2. The control sleeve 25 is turned in the clockwise sense by the ends of the pin or dog 38 engaging into the control slots 25a and moving in a plane towards the rear.

According to Fig. 4 at the beginning of the rotation of the control sleeve 25 the arm 27a of the locking pawl 27 is supported by a cam 15e of the cylinder casing, so that the spring-biased arm 27b can rest itself into the next interstice 17a of the stationary driving charge casing 17 only after a certain path of rotation, after the arm 27a is released.

The frictional force generated during the rotation of the control sleeve 25 by the spring-biased arm 26a of the switching pawl and acting on the driving charge casing, acts in the sense of a rotation thereof in the clockwise direction. This rotation is however, prevented by the locking tooth 37. Towards the end of the rearwardly directed cocking movement of the auxiliary piston and accordingly of the rotation of the control sleeve in the clockwise sense the arm 26a of the control pawl 26 engages into an interstice 17b, while at the same time its other arm 2Gb moves under the arm 34a of the locking pawl 34 and turns the latter away from the locking position, i.e. out of the interstice 17c (Fig. 5).

At the end of its cocking movement the rear portion 14b of the auxiliary piston makes an impact on the shoulder 15f of the bore of the cylinder casing, whereby the auxiliary piston as a whole is thrown back towards its starting position by the action of the loaded return spring 16. The auxiliary piston reaches this position, before the slider member has run right into its forward end position. During this forwardly directed return stroke of the auxiliary piston the switching stroke of the driving charge casing takes place, in that the control pawl 26, which rotates with the control sleeve 25 in the counterclockwise sense, turns by its arm 26a the driving charge casing 17 by one pitch, whereby the next cartridge 20 is brought into the tiring position. The control pawl 27 projecting firstly into the interstice 17a prevents the driving charge casing from preceding the control pawl 26 owing to the rotational impulse imparted to it by the impact of the latter, and from turning further than would correspond to one pitch of the cartridge chamber. Towards the end of the switching stroke the cam 25b of the control sleeve runs under the arm 34b of the locking pawl 34 and forces the same back into the locking position, whereby at the end of the switching stroke the driving charge casing makes an impact on the pawl and is thereby brought to a standstill. The driving charge casing is then again restrained against rotation in either direction by the locking pawl 34, and by the locking tooth 37 having engaged on its rotation into another interstice. The pawl mechanism acts accordingly as a freewheel clutch which couples the control sleeve when the same is set in rotation by the auxiliary piston during the return stroke of the latter, with the driving charge casing.

After renewed operation of the ignition device and iguiting of that driving charge cartridge, which is actually in the ring position, the cocking and following-up operation described hereinabove repeats itself.

In the embodiment of the invention described hereinabove by way of example, the spring 16 is provided as an accumulator of the energy required for moving the driving charge casing 17. Another possibility of moving the driving charge casing consists in that the slider memer 4 thrown back by the piston 14 when returning into the starting position pushes the same forward and thus supplies .the energy for the switching of the driving charge casing.

While I have described herein and illustrated in the accompanying drawings what may be considered a typical and particularly useful embodiment of my said invention I wish it to be understood that I do not limit myself to the particular details and dimensions herein described and illustrated; for obvious modications will occur to a person skilled in the art.

What I claim as my invention and desire to secure by Letters Patent, is:

In a cocking device for automatic firearms the combination comprising a breech mechanism, a stationary cylinder body extending along a longitudinal axis, a sealing surface on said cylinder body, a pressure chamber in said cylinder body, a casing rotating around the longitudinal axis, a plurality of cartridge chambers arranged around the longitudinal axis within said casing and sealed by said sealing surface, fluid pressure transmission means for connecting said pressure chamber with one of said cartridge chambers, a reciprocating piston within said cylinder body having a normal position and an operating position which seals said pressure chamber unilaterally and is in driving connection with said breech mechanism, to operate the latter by said piston upon a movement of the latter from the normal position to the operating position effected by the pressure within said pressure chamber, resilient means for biasing said piston to said normal position, driving means connecting said piston with said casing for a stepwise rotation of said casing during the resulting displacement of the piston accomplished by said resilient means from the operating position to the normal position, said driving means comprising a sleeve 2,96,`o'so rotatable on said cylinder body and which is provided of the back and forth rotation of said sleeve to said step'- with guide ways, further guide ways on said cylinder body wise movement of said casing. forming an angle with said rst mentioned guide ways,

dogs in driving connection with said piston engaging said References Cited in the me of this patent first mentioned and said further guide ways to convert 5 said reciprocation of said piston into a back and forth UNITED STATES PATENTS rotation of said sleeve, and ratchet and pawl means en- 2,821,116 Schwager et al Jan. 28, 1958 gaging with said casing and said sleeve for a conversion 2,882,794 Bornheim et al. Apr. 21, 1959 

